SLOP3255 · Week 03 · Mapping design
Mapping numbers to sound#
A mapping is a model: it decides which difference a listener is allowed to notice.
Auditory dimensions are not interchangeable#
| Sound dimension | Strong for | Watch for |
|---|---|---|
| Pitch | order and contour | range, tuning and musical expectation |
| Duration | interval and event density | slow playback |
| Loudness | salient contrast | safety and device differences |
| Timbre | categories and layers | hard-to-name differences |
| Stereo position | relative location | headphones and hearing asymmetry |
Data frequency is not automatically pitch#
The same word, frequency, can name a measured repetition rate or an audio oscillator. Do not collapse them.
Linear or logarithmic?#
| Input | Linear pitch | Log pitch |
|---|---|---|
| 1 | 220 Hz | 220 Hz |
| 10 | 260 Hz | 440 Hz |
| 100 | 660 Hz | 880 Hz |
Linear mapping preserves equal differences. Log mapping foregrounds equal ratios. The task chooses the scale.
Continuous or quantised?#
Continuous pitch keeps small differences. Quantised notes are memorable, but they invent thresholds that the data did not contain.
One sound dimension, one first job#
Time
sample order
Pitch
measured value
Timbre
quality flag
When two data dimensions compete for pitch, a listener cannot know which one moved. Independence is a design resource.
Three mappings of one sequence#
| Sequence | Rule | Question supported |
|---|---|---|
| 2, 4, 8, 4, 2 | value → pitch | where is the maximum? |
| 2, 4, 8, 4, 2 | value → interval | where does pacing slow? |
| 2, 4, 8, 4, 2 | value → timbre | which category dominates? |
The source is fixed. The supported inference changes.
Evaluate a question, not a vibe#
“It sounds cosmic” is an aesthetic response, not an evaluation task.
Listening Lab 03 · Output: mapping scorecard
Mapping shoot-out#
Task
Render one five-value sequence with pitch, interval and timbre. Test each version with a defined question.
Deliver
- complete rule
- listener result
- selected mapping
Keep the source values and playback duration fixed while comparing mappings.